If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illuminates the engine trouble warning light and provides the engine with alternate operating instructions that are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are programmed for each sensor in order to provide the engine with alternate operating instructions that enable the engine to continue to operate or stop operating, depending on the conditions.
Self-Diagnostic Function table

Ecu self-diagnostic function
Troubleshooting methodThrottle position sensor
1. Check:
Throttle position sensor
a. Connect the digital circuit tester to the terminals
of the throttle body sensor assembly
coupler as shown.
Positive tester probe →
gray/red terminal "1"
Negative tester probe →
gray/black terminal "2"
b. Measure the throttle pos ...
Troubleshooting
Any of the following fail to light: turn signal lights, brake light or
indicator lights.
The horn fails to sound.
The fuel gauge fails to operate.
The speedometer fails to operate.
NOTE:
Before troubleshooting, remove the following part(s):
1. Seats
2. Fuel tank
3. Left upper ...
Removing the generator
1. Remove:
Generator rotor nut "1"
Washer
NOTE:
While holding the generator rotor "2" with the
sheave holder "3", loosen the generator rotor
nut.
Do not allow the sheave holder to touch the
projection on the generator rotor.
2. Remove:
Generator rotor "1"
(with the ...